conductor-oss/conductor · error · IllegalArgumentException

missing wrapper class:

Error message

missing wrapper class: 

What it means

Thrown as IllegalArgumentException by WrappedType.wrap after computing the expected wrapper class name (value simple name + suffix) and not finding a MessageType registered under that simple name in TypeMapper. protogen expects a generated wrapper message (e.g. StringMap) to exist for the collection/map value; if discovery did not declare it, wrapping cannot proceed.

Source

Thrown at annotations-processor/src/main/java/com/netflix/conductor/annotationsprocessor/protogen/types/WrappedType.java:35

import javax.lang.model.element.Modifier;

import com.squareup.javapoet.MethodSpec;
import com.squareup.javapoet.TypeName;

public class WrappedType extends AbstractType {
    private AbstractType realType;
    private MessageType wrappedType;

    public static WrappedType wrap(GenericType realType) {
        Type valueType = realType.getValueType().getJavaType();
        if (!(valueType instanceof Class))
            throw new IllegalArgumentException("cannot wrap primitive type: " + valueType);

        String className = ((Class) valueType).getSimpleName() + realType.getWrapperSuffix();
        MessageType wrappedType = TypeMapper.INSTANCE.get(className);
        if (wrappedType == null)
            throw new IllegalArgumentException("missing wrapper class: " + className);
        return new WrappedType(realType, wrappedType);
    }

    public WrappedType(AbstractType realType, MessageType wrappedType) {
        super(realType.getJavaType(), wrappedType.getJavaProtoType());
        this.realType = realType;
        this.wrappedType = wrappedType;
    }

    @Override
    public String getProtoType() {
        return wrappedType.getProtoType();
    }

    @Override
    public TypeName getRawJavaType() {
        return realType.getRawJavaType();
    }

View on GitHub (pinned to cf7c3e4a8a)

Solutions

1. Confirm the wrapper message for the value type is generated and registered before WrappedType.wrap runs.
2. Ensure value type simple names follow the naming protogen derives (Simple + suffix like 'Map').
3. Use scalar value types where possible so no wrapper is needed (List<String>, Map<String,Integer>).
4. If a custom wrapper is intended, declare it via TypeMapper.declare so get(className) resolves it.

Example fix

// before — value type has no registered wrapper
Map<String, Custom> map; // 'CustomMap' not declared
// after — use scalar value, or ensure CustomMap wrapper is generated
Map<String, String> map;  // scalar needs no wrapper

String wrapperName = ((Class) valueType).getSimpleName() + realType.getWrapperSuffix();
if (TypeMapper.INSTANCE.get(wrapperName) == null) {
    throw new IllegalStateException(
        "No protogen wrapper registered for " + wrapperName + "; generate/register it first or use a scalar value type.");
}

When it happens

Trigger: A collection/map field whose value requires a wrapper (non-scalar value) but the corresponding wrapper message class was never declared — e.g. the wrapper source was not generated/registered, or the value type's simple name does not match the expected wrapper naming convention.

Common situations: Custom value types whose names do not follow the suffix convention expected by protogen; running protogen without first generating the wrapper messages; a partial codegen where wrapper messages were excluded.

Related errors

• cannot map non-scalar map key:
• Cannot map type:
• duplicate type declaration:
• cannot wrap primitive type:
• missing Jar file

AI-assisted analysis of conductor-oss/conductor@cf7c3e4a8a (2026-08-14). Data as JSON: /api/errors/5c2baf4965d917ef. Report an issue: GitHub.